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United States Patent | 5,689,808 |
Sandahl ,   et al. | November 18, 1997 |
Apparatus for effecting simulcast data broadcasting includes a source of information, a network control unit, and a plurality of transmitters. The network control unit includes a high-stability timebase which is coupled to the source of information to produce a signal clocked from the high-stability timebase and containing data and digital identifying information. Each of the plurality of transmitters is coupled to the network control unit to receive the signal, and each has a modulation-generating timebase. Each modulation-generating timebase is phase locked to the high-stability timebase by way of synchronization information included in the signal, and each is adjusted by a corresponding correction value provided by the network control unit, thereby providing a highly accurate coincident modulation of the plurality of transmitters during a radio broadcast containing the signal.
Inventors: | Sandahl; Joel E. (Quincy, IL); McFarland; Scott A. (Quincy, IL); Nagel; John F. (Quincy, IL) |
Assignee: | Motorola, Inc. (Schaumburg, IL) |
Appl. No.: | 641367 |
Filed: | March 10, 1994 |
Current U.S. Class: | 455/503; 375/356 |
Intern'l Class: | H04B 007/00 |
Field of Search: | 455/49.1,51.1,51.2,56.1,103,105,53.1,70,71 375/356,357,362,363 |
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5127101 | Jun., 1992 | Rose, Jr. | 455/51. |
5201061 | Apr., 1993 | Goldberg et al. | 455/51. |
5218717 | Jun., 1993 | Reitberger | 455/51. |
5220676 | Jun., 1993 | LoGalbo et al. | 455/51. |
5257404 | Oct., 1993 | Goreham et al. | 455/51. |
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